The term “battery” is used herein to include accumulators. In a conventional lead acid battery it is customary to connect together the plates of each stack by means of a lead strap or post which is fixed to aligned lugs or tabs on the plate. As is explained in detail in WO 94/16466, the disclosure of which is incorporated herein, with bigger moulds problems can arise in flowing sufficient lead into the cavities in the moulds and the solution postulated in that case was to have a pair of these passages for a set of cavities so that one half of the set was fed from one of the feed passages, whilst another half of the set was fed from the other. As is discussed in WO 94/16466, this approach had many advantages and the mould has been extremely successful.
However, problems have arisen in getting consistent post or strap quality, because, as the applicants have now appreciated, that part of the set which lies nearest the pump can be filled up to half a second earlier than the second set of cavities, fed by the other passage, which are more remote from the pump. As the lugs can only be dipped at a single instant it is very difficult to optimise the moment of dipping in relation to cavity fill and this can affect not only the final shape of strap or post moulded, but also on the quality, because the thermal exchange that takes place on dipping will vary in dependence on the amount of lead in the mould.
Attempts have been made to solve this problem by very accurate automisation of the system, but the applicants have now realised that surprisingly a much cheaper and simpler solution can be adopted.